Large-scale genetic and neuropathological studies have since confirmed GBA1 as the most prevalent genetic risk factor for sporadic PD and DLB, present in approximately 5–10% of PD cases and up to 20% of DLB cases [4,5], and, when affected, often show earlier onset, more rapid progression, and increased cognitive impairment compared to idiopathic cases (Table 1). This evidence concerns the gene GBA1 and Lewy body dementia.